Rear mech trouble?

[Dr.Robotnik]

When putting on the 9 speed cassette did you remove the ring spacer on the freehub which was behind the 8 speed cassette?

8 and 9 speed cassettes go on the same free hub but the 8 speed has a spacer and the nine speed doesn't.

If you've left it on it might be pushing the cassette to close to the drop out.

If you've done all that and that's all fine and nothing rubs then I don't know what to suggest.

 

[FluffyChicken]

This will not answer your chain is close question (you are using 9-speed chain?)

But did you play around with the b-tension screw, that small screw puching against the frame tab.
You'll need to set that up last


There is also another tension screw, but I've rarely seen it altered.

 

[Zendog]

Just a side thought....had your hanger checked for alignment recently? Even if you treat the bike with the utmost respect, pedaling forces alone can mess up the alignment. If you do not have a truing tool then your LBS is your next stop, or borrow one from someone who does. If it does have to be re-aligned then you will probably need to re set the adjustments again.

 

[orange71]

as fluffy chicken said you need a 9 speed chain as these are narrower than 7/8 speed chains as the gaps between the cogs are smaller. Apologies if you are going :roll: right now if I'm stating the bleeding obvious!

 

[daj]

oooowww you may have a good point you know .... The chain came with the chainset but the chainset is a M950 which is 8 speed ( though thats not to say it was running a 9 speed ) Bugger I will go and have a look and compare

I did think about the mech being bent when it kept skipping but everthing seems good now ... I just thought it looked close to the frame.

 

[jonnyboy666]

you followed my instructions then? thats the way i have always done it coz it sets the limit screws first, then it's just tensioning the cable correctly.

i don't recall there being a spacer on 8 speed cassettes though, none of mine have one behind the cassette and i have used shimano and sram 8 and 9 speed on 8 or 9 speed hubs and have never had that issue before. there is sometimes (depending on the model) a spacer that sits between the 6th and 7th sprocket on 8speed cassettes that sometimes people put in the wrong place and that would affect the indexing. the only time i have used spacers is when using a 7speed on an 8/9 hub, and it would always be a hope one.

also the b tension screw usually doesn't need adjusting from the factory unless you have a frame that leaves the mech with not alot of tension on the b-tension assembly (the main sring assembly that screws into the hanger) if needed, you would screw it in clockwise, you will need to do this if when in first sprocket the top jockey wheel teeth catch on the biggest sprocket, they make a funny sound when this happens that is quite loud and obvious.

and to me the space you have, or lack of it, looks ok, the drop outs are quite wide which can make it look tighter and if all the gears work and index correctly then that suggests the hanger is straight.

edit-- 9speed chain, it's a must, the 8speed wouldn't work properly out on the trail but maybe on a workstand with no pedaling pressure.

 

[Dr.Robotnik]

i don't recall there being a spacer on 8 speed cassettes though,

They exist, don't you worry. We had one come through the shop the other day! A guy wanted us to switch his 8 spd cassette to 9spd, another mechanic (not me) doing the job tried to fit the new cassette and couldn't get the lock ring to reach the threads properly. I noticed the spacer, once removed, it was all sorted.

However I have no idea what's standard anymore (I was last into mtb's in the 90's) though so don't expect it to be on every bike....

That's not the case here though as on closer inspection of the chain it appears an 8spd. So forget everything I just said

 

[daj]

Yep its an 8 speed alright :roll:

Now I do have a 9 speed chain but will it be compatible with the bloody chainset !?!? :shock:

 

[MikeD]

Not really.

 

[hamster]

Yes, I got caught by the 8 speed spacer trick the other day - on a set of Mavic wheels. It's really thin, not some big 3mm+ thing like putting a 7s onto an 8/9 freehub.

Never seen one before either :shock: